Drill



DRILL Filed March 18, 1949 41 INVENTOR. E i 7 76 G5 4G 6G VICTOR. s. KARBOWSIU 46 m I 4| i: e 9& II v 39 4O 39 4o ATTORNEY.

Patented Apr. 15, 1952 2,593,035 DRILL Victoi" S.Karbowski, Lima, Peru Amie-stagnant 18, 1949;; Serial Nb? 82,165 In cabana January- 8, 1949" 4 Claims." (01. 255

This invention relates to drills suitable for drilling rock and is herein describeol' in some detail as' embodied in an expansion drill, adapted to produce a blast hole with an enlarged, bottle-likeor ball-like chamber at the inner end of the blast hole. Such a chamber may hold a much greater charge of blastingchargethan the usual cylindrical drilled opening.

Not only does such a chamber hold more explosive than the usual cylindrical drill hole, but

the relatively narrow opening of thechamber serves as a partialtamping or plugging over the explosive in the hole. I

As a result, the charge, when exploding, is more concentrated, is deeper in the rock, and may be caused to break the rock in larger lumps with less charge of explosive.

Thus, the expansion drill enablesblasting to be done with less explosive and with less depth of drill hole. In this way, drilling time is saved, as well as man-hours.

Another advantage is the reduction in amount of the detrimental silicosis powder produced in drilling for each charge of explosive.

The drilling device may take any one of severalqforms, but in each form is free from the objectionable weaknesses of prior devices in'-' tended'to serve as expansion drills, but which relied on pivots "that failed to withstand the strains and shocks incidental to drilling.

In the device of the present invention, the:

preferred form provides a V-shaped track or seat as ,a circular arc in which the V-shaped face of the back of the cutting element seats itself to provide a large area to carry the blows of the drill on the rock, and the large pivot, re-' ceives only part of any such blow. Thus a' highly rugged device is provided.

Other features and advantages will hereinafter appear.

:In the accompanyingdrawings:

Fig. 1 shows a side view of one form or cutting end of its drill. V Fig.2 is a side view; broken away to show the internal structure.

Fig. 3 is a viewof an alternative'form with screwed on removable head.

Fig. 4 is a front View of the same.

Fig. 5 is a face view of one form of the pivoted r cutters. V 4

Fig. 6 is an edge view of" the same. Fig. 7 shows a fourth form in side view. Fig. 8 is an end view of the parts in Fig. 7.

Fig. 9"is an end view of; still another form.

and as lyingin aj'V-shaped' circular afc23 formr ing a track intheidrill end 24, so' that 'thebodyf 2| may rotate over a, considerable angle in track" 23and face it over a large'area.

The drill shank orend 24in Fig. .1 carries in" a transverse hole 25 or bore a heavy bolt'26 which passes through center holes 21 in the? two bodies 2| and serves as a shaft on which:

the bodies 2| may turn, but fits closely enough to keep the l-shaped backs 22 well seated in the V -shaped tracks 23.

" The bolt 26 includes a rounded head 3| lying outside'of one body 2|, but lying wholly within" the imaginary outside prolongation of the; sha-nk 24, and the other end of the bolt 25 also 'f terminates within the imaginary prolongation of the shank 24 and is pierced outside the other body 2| by a transverse hole to receive aheadd splitpin 28, so the pin 28 may have its end split open to bear against the outside of thef other body 2| and securely hold'the bolt 26 "and" both bodies 2! assembled.

Each body 2| istapered to cause the cuttihg l edge 2!] to form an angle of about 60 andjis shown as about oneefifth of the thickness of the enlarged shank 24.

The taper or V-shape of the cutting edge'ex tends Wholly around the periphery ofthelbody and the track 23 is out to face and'fit the'l tapered edge 20', so'that the 'body 2| seats itself-'- in the track 23 at any angle at which thef'body 2| stands and thus receives theshocks of'drill ing over alarge area.

across the opening drilled on the rocklflas in dicated in dotted lines in Fig. l. k

Thus the opened edges 2|! drill a hole of maximum possible reach of the edge's 2ll onthe two bodies 2|, or nearly double the diameter of the hole drilled'by the circular boundary diameter of the bodies 2|.

As appears in Fig-'1, the hole 25 furnishesa, bearing about twice the thickness'of a body 2|" in length and so gives" considerable bearing "sup-i" port for'the shaft or bolt 26..

The bolt 26 is shown of a diameter ab outequal to its length between bodies 2| and about one? third the total circular diameter of a body'fll. As appearsflin Figs; 1 and 2, theends '32 of the tracks 23 are cutaway at an angle, so that whole tapersurface of each cutting edge 2llbegins to lie on the track 23 at about thesame: time, distributing the load uniformly'on the taper surface of the body 2|.

In order to make sure that'bodies or, cutting" blades 2| swing outwardly rather-than'inwardly,'each is provided with aninwardly facing lug 34 (dotted lines in Fig. 1) or offset adapted to 9 lie against a cooperating step or lug 29 on the flat face of drill end 36, when a cutting blade lies so as'to out directly axially of the drill body. The end 35 is shown as rounded at its tip.

- 4 forward. The lug 61, therefore, prevents the cutter from turning beyond dead center.

Figs. 10 and 11 also show a removable seat 68 lying between the ears 4|, 42 and resting its fiat The cutting blade 2| C however, Sw freely back 69 on the bottom 19 of a channel H between to carry its point 29 beyond the body of the drill on the opposite side. The lug 34 lies, preferably, on the inner face of its cutting blade 2|, where it is least exposed said ears. The seat 68 is provided with triangular arcuate channels 12 in which the nearly circular backs 22 of thecutters 39 and 49 seat themselves snugly. The seat 68 is shown as including a neart d m and lies on a portion of the edge that 1y square shallow projection 13 on its back which normally is clear of the rock in drilling.

Thus when the drill body is lifted out of the drilled'hole the points 29 of the cutting bodies swing in on their shaft and allow the drill to fits into a correspondinghollow 14 in the end of the body 24, thus holding the seat 69 centered.

While the backs 22 of the cutters 39 and 49 of Figs. 10 and 11 are described above as nearly be Withdrawn f o the larger chamber into the circular, their arcs end in long tangents 16, and

smaller cylindrical drill hole.

The alternative form of drill head shown in Figs. 3 and 4, provides a screwed-on head 31, the screw being shown at 38, where the enlarged head unites with the shank 24. i

In the form shown in Figs. 3 and 4, the cutting blades 39 and 49 lie against each other between two ears 4!, 42 which project beyond the head 31 and carry a heavy shaft bolt 43 with x the supporting channels in the seat 68 are shown as carried straight outwardly in an extension of the seat 68 reaching the maximum diameter of the drill head 3'! in these figures.

The cutters 39 and 49 of Figs. 10 and 11, are

shown with convex cutting edges 16, and these seem to'be advantageous in cutting relatively soft rock such as shale.

Moreover, after a drill hole has been enlarged slotted head 44 O e e and Split P both at its bottom by the cutters of Fig. 1 or 3, it may lying outside the ears 4!, 42. But the whole bolt 43- lies within an imaginary prolongation of the head 31 and the two cutting edges 39, 49 may be held to lie within that prolongation.

In the form shown more in detail in Figs. 5

and 6, each cutting blade 39 and 40 is shaped in outline like a cutter blade of Fig. 1, but carries on its outer face a pin or lug 46 adapted to lie against a pin 46a welded on the arcuate periphery be further enlarged as it is further advanced by the cutters of Fig. 10, thus making shoulders above the charge of explosive on the end of the drill hole.

The drillbody 24, the drill head 31, and the shallow projection 13, are shown with central 1 small longitudinal hollow bore 15, extending down to the channel.

Having thus described certain forms of the inof each ear 4!, 42 when the points 29, 29 point vention in some detail, what is claimed is:

forward. Thus, neither blade can ever swing inwardly beyond center, but is free to fall into the full line, Fig. 3, position.

In the form of drill head shown in Fig. '7, two

1. An impact drill including a shank, a pivot passing through the shank transversely of its length, circular arc faces on the shank struck from the pivot center and forming V tracks, flat cutting edges 41, 48 are separately mounted in disc cutter blade members each having a circular spaced parallel pivot cross shafts 49, 59, which may take the form of headed bolts 5|, 52, held againstslipping out by split pins 53, 54.

The cutting edges 41, 48 may take the form of arc V-shaped bearing back portion adapted to fit and slide on a V track, and a V-shaped cutting portion formed by portions of the blade extending on a tangent from the V-shaped circular are smaller bodies but otherwise much like the bodies hearing portion and meeting at point so that 2| of Fig. 1, though mounted between extension ears (see Fig. 8), projecting from the drill body 24. Preferably, the cutting edges 41, 48 can turn only as far as to bring their tangential edges 56 parallel to but below the bottoms of the ears 55. It is impossible for any edge to swing so its point 41 or 48 swing-s inwardly, since the other edge blocks it.

A four-edge drill head is shown in Fig. 9, in which four L-shaped ears 59 project from the drill shaft axially, with transverse headed pivot bolts .69 passing through adjacent arms of the Us. Each of the four pivots 60 may carry a cutting'edge member 61, so that their points, when swung out, as shown in dotted lines in Fig. 7, cut an enlarged bore, and when swung in lie on or within the circle around the ears 59, as do the outer edges of the cutting edge members 41, 48

of Fig. 7 on the circle of the ears 55 in that figure.

In the form shown in Figs. 10 and 11, the cutters 39 and 49 of Figs. 3 and 4, turn on a bolt 62 having a depression 63 in one head 64, shown as expanded as a rivet head in the countersunk end 65 of the bolt opening through the ears-4i 7 adjacent ear 4! or 42 when the cutter point points 50 arrested against turning backward beyond its center.

3. A device according to claim 1 in which the shank is formed with a projecting lug through which the pivot passes and which lies between 55 the cutter blades.

4. A device according to claim 1 in which the blades lie against each other and the pivot passes through the blades and through a projecting lug of the shank outside each blade.

60 VICTOR s. KARBOWSKI.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date Stokes l Oct. 8,1940 

